1. Valisa et al C-mod Ideas Forum, 8 April- 2009 Electron heating and Ni / Mo Pump Out L Carraro, I Predebon, ME Puiatti, M Valisa ( Consorzio RFX Padova) C Angioni ( IPP Garching) J Rice et al ( C-mod) C-mod Ideas Forum, 8 April 2009

2. Valisa et al C-mod Ideas Forum, 8 April- 2009 We do not have a comprehensive understanding of the impurity behavior - Many plasma scenarios /machine peculiarities / variety of impurities ( A, Z, Z/M) ITER: accumulation of heavy impurities is a concern and a feedback system on the impurity profile is desirable. Many experiments worldwide: central RF (especially on the e-channel) exerts a pump out effect on impurities - AUG experience with W wall: central ECRH routinely used to avoid W accumulation - In AUG ITG/TEM-like turbulence apparently drives the outward flow ( Angioni et al Plasma Phys. Control. Fusion 49 (2007) 2027 ) Motivation

3. Valisa et al C-mod Ideas Forum, 8 April- 2009 In JET : ICRH (H or He3 minority ) does flatten Ni and Mo profiles ( Puiatti et al PoP 2006, Giroud et al IAEA 2006, Carraro et al EPS 2007 ) JET data unexplaplained in terms of turbulence. GS2 simulations predict ITG dominated spectra with associated inward flow. Observation: JET and AUG occupy different regions of the parameter space In JET @ r/a ~ 0.2, R/LTe 8 In AUG @ r/a ~ 0.2 R/LTe > 8, R/LTi < 5 Is in JET transport neoclassical? Other physics? Carraro et al EPS 2007 Central JET & AUG : different regions of parameter space

4. Valisa et al C-mod Ideas Forum, 8 April- 2009 Scan of ICRH power (in He3 or H minority schemes) to produce the JET type of plot LBO Ni and/or Mo injection ( depending on various considerations ) Shot required 4-5 good shots per species and plasma scenario Analysis - Use M.Mattioli’s code (or others local) to simulate SXR and emission lines for v/D - Use GS2 to analyse turbulence spectrum and associated flow. -Use Nclass for evalutaion of neoclassical transport - Watch q, Te/ Ti, R/LTe, R/Lti, R/Lne and rotation ( Camenen et al PoP 16, 012503 2009 ). - Requirements : LBO system,xuv spectroscopy, good SXR, Te, Ti, ne profiles. suitable target plasma ( H mode/ EDA) with (small or no sawteeth) - To be done : careful selection of target plasma, of best impurity, of power scan entity - NB : light impurity analysis (e.g B or He & DNBI) could be studied in the same shots (Z dependence of transport) WHAT WE PROPOSE TO DO ON C-mod